The present invention relates to ovens for continuously heating ingots, sheet material, and the like of light metal or light metal alloy and, in particular, to a relatively high efficiency oven which utilizes the exhaust gases of the heating device to help heat the material more efficiently thereby causing a minimum of environmental contamination.
Prior art ovens used for heating raw material such as ingots or sheet strips utilized a very small portion of the available heat produced by the heating burners to heat material. The exhaust gases frequently leave the oven at relatively high temperatures thereby contaminating the environment and making poor use of the available energy. Wasting the fuel and heat generated thereby increases the cost of the heating process, increases the time required in order to process the material and increases environmental contamination.
For many years inventors have attempted to overcome these disadvantages and have developed processes wherein the thermal efficiency of the oven has been improved by pre-heating the air used in the combustion process with the exhaust gases. However, this approach has not been proved successful. Other approaches include a process wherein the cold fresh air to be utilized in the combustion process is pressurized by a ventilator or fan and warmed by a heat exchanging means which utilizes exhaust gases as a heat source. Additionally included is a turbine system which at the same time increases the speed of the hot exhaust gases, thus bringing about recovery of some heat, which is normally lost in the exhaust gases. The inherent disadvantage with this type of process lies in the fact that large amounts of heat are still lost. It has also been found that this process tends to heat the material at a relatively rapid rate which in itself may be a disadvantage.
It is desirable to provide an industrial heating oven which does not have the shortcomings known in the prior at, does not use abnormal amounts of energy, and can provide even heating of the material by utilizing the exhaust gases more efficiently. Industry today has a need for processes which have increased efficiency and do not contaminate the environment. The present invention overcomes the shortcomings found in the prior art by providing an efficient means for raising the transfer efficiency of objects to be heated without requiring additional fuel or contaminating the environment.
Therefore, it is an object of the present invention to provide a continuous flow oven for heating material such as ingots, sheet material and the like with relatively low environmental contamination.
Another object of the present invention is to provide a means for using the heat generated in the exhaust gases of the heating process to aid in the heating of the material.
The above objects, as well as further objects and advantages of the present invention, will become readily apparent after reading the description of a non-limiting illustrative embodiment and accompanying drawing.